Leakage-proof needle seal

Abstract

The utility model discloses a leakage-proof needle seal which comprises a sealing assembly for a needle head of a sample injection needle to extend in, and the lower end of the sealing assembly is fixedly connected with a sealing support; the sealing assembly comprises a sealing gasket and a sealing hoop arranged outside the sealing gasket in a sleeving mode. A channel penetrating through the sealing gasket in the axial direction is formed in the sealing gasket and comprises a first channel body, a second channel body, a third channel body and a fourth channel body which communicate with one another in sequence. The first channel and the third channel are each of a conical structure, and the small ends of the first channel and the third channel are arranged in the negative direction of the Y axis. According to the scheme, the shape of the channel is improved, and the double-cone-shaped channel is arranged, so that the sealing gasket has a multi-sealing function, the working time can be prolonged, the service life of the sealing gasket is prolonged, and the replacement frequency is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of injection needle sealing devices, in particular to a liquid leakage-proof needle seal. Background Art

[0002] Chromatograph is an efficient, accurate and sensitive chemical analysis instrument that can be used to separate, identify and quantify various chemical substances. It has a wide range of applications in many fields, such as blood analysis, clinical testing, pharmaceuticals, life science research, and animal and plant quarantine. The injection needle is an indispensable component of the chromatograph, which is mainly used to remove the sample to be analyzed to achieve sample distribution and transfer. In order to ensure the sealing of the connection between the injection needle and the chromatograph system, a sealing device, namely a needle seal, is generally set at the injection port of the chromatograph. It usually includes an annular elastic gasket. The needle seal can prevent sample leakage or contamination inside the injection needle. However, during use, the needle seal often has problems such as leakage and poor sealing effect. This is because after long-term use, the pressure applied by the injection needle to the needle seal may cause fatigue, aging or even damage to the elastic gasket, resulting in the needle seal losing elasticity or deformation, and the opening size of the connection between the elastic gasket and the needle port becomes larger, and it can no longer seal the injection needle. Therefore, the service life of the needle seal is short and needs to be replaced frequently. Utility Model Content

[0003] In view of the above-mentioned deficiencies in the prior art, the utility model provides a leak-proof needle seal, which solves the problem that the needle seal in the prior art has a short service life and needs to be frequently replaced.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0005] Provided is a leak-proof needle seal, which includes a sealing assembly into which a needle of an injection needle extends, and a sealing support is fixedly connected to the lower end of the sealing assembly; the sealing assembly includes a sealing pad and a sealing hoop sleeved on the outside of the sealing pad;

[0006] A channel is provided inside the sealing gasket and runs through it axially, and the channel includes a first channel, a second channel, a third channel and a fourth channel which are connected in sequence; the first channel and the third channel are both conical structures, and the small ends of the first channel and the third channel are both set toward the negative direction of the Y axis.

[0007] The utility model has the following beneficial effects: by improving the channel shape, the sealing gasket has multiple sealing functions. After the needle is inserted into the sealing gasket, the operator feels resistance and first forms a seal at the connection position between the first channel and the second channel. When the first seal fails, the needle is pressed down continuously each time the sample is injected until a seal is formed again at the connection position between the third channel and the fourth channel. The sealing gasket can continue to work, prolong its service life and reduce the replacement frequency.

[0008] The sealing effect formed by the needle at the connection position between the first channel and the second channel is closer to a line seal rather than a surface seal, because the injection needle needs to frequently pierce the needle seal, which is a dynamic seal, and the needle is also conical. The line seal can seal along the contour of the needle and can better fill the gap between the needle and the sealing pad. Therefore, the line seal can usually withstand higher pressure. Therefore, for the injection needle, the line seal is better than the surface seal.

[0009] Furthermore, the second channel has a conical structure, and its small end is arranged toward the positive direction of the Y axis. This is more conducive to the needle forming a line seal. As the diameter of the second channel gradually increases, the needle located in the second channel portion may not contact the second channel wall, so the seal at this time can be closer to a line seal.

[0010] Furthermore, the second channel is cylindrical, and the diameter of the second channel is equal to the diameter of the small end of the first channel and the diameter of the large end of the third channel. The second channel of the cylindrical structure can appropriately reduce its channel volume relative to the conical structure, which is conducive to reducing dead volume.

[0011] Furthermore, the sealing gasket includes a first cylinder and a second cylinder formed in one piece, the diameter of the first cylinder is larger than the diameter of the second cylinder; the sealing hoop is in a shell shape, which is tightly connected to the second cylinder, and the lower end surface of the first cylinder is supported on the upper plane of the sealing hoop; the strength of the sealing hoop is greater than the strength of the sealing gasket. When the sealing gasket is expanded by force, the sealing hoop will protect the sealing gasket, reduce its deformation, and extend the service life of the sealing gasket.

[0012] Furthermore, a through hole is provided inside the sealing support axially therethrough, a steel pipe is fixedly connected to the through hole, both ends of the steel pipe extend out of the sealing support; the internal cavity of the steel pipe is connected to the fourth channel.

[0013] The beneficial effect of the above technical solution is: one end of the steel tube extending out of the sealing support contacts the sealing gasket to form a seal, and the other end is connected to the six-way valve on the chromatograph, so that the sample in the injection needle flows through the internal channel of the sealing gasket, the internal cavity of the steel tube, and the six-way valve to enter the chromatographic column or mass spectrometer.

[0014] Furthermore, the longitudinal section of the first channel passing through the axis is an isosceles trapezoid, the angle of the intersection of the extension lines of the two hypotenuses is 20 to 30 degrees, and the diameter of the large end of the first channel is 1 mm to 1.2 mm.

[0015] Furthermore, the fourth channel is cylindrical, and its diameter is equal to the diameter of the small end of the third channel; the diameter of the small end of the third channel is smaller than the diameter of the small end of the first channel. By providing the first channel with a large tapered hole and the third channel with a small tapered hole, the hole diameter can be reduced to match the cavity in the steel pipe below, thereby achieving the purpose of reducing the dead volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of an embodiment of a leak-proof needle seal;

[0017] Figure 2 A schematic diagram of another embodiment of a leak-proof needle seal.

[0018] Among them, 1. sealing assembly; 11. first channel; 12. second channel; 13. third channel; 14. fourth channel; 15. sealing gasket; 16. sealing hoop; 2. injection needle; 21. needle body; 22. needle head; 3. sealing support; 5. steel pipe; 51. cavity. DETAILED DESCRIPTION

[0019] The specific implementation methods of the utility model are described below to facilitate technical personnel in this technical field to understand the utility model, but it should be clear that the utility model is not limited to the scope of the specific implementation methods. For ordinary technical personnel in this technical field, as long as various changes are within the spirit and scope of the utility model defined and determined by the attached claims, these changes are obvious, and all utility model creations using the concept of the utility model are protected.

[0020] like Figure 1-Figure 2 As shown, the injection needle 2 includes a needle body 21 and a needle head 22 with a conical structure. The anti-leakage needle seal of this solution includes a sealing component 1 for the needle head 22 of the injection needle 2 to extend into, and a sealing support 3 is fixedly connected to the lower end of the sealing component 1; the sealing component 1 includes a sealing pad 15 and a sealing hoop 16 sleeved on the outside of the sealing pad 15;

[0021] The sealing gasket 15 has an interior with a channel running through it axially, and the channel includes a first channel 11, a second channel 12, a third channel 13 and a fourth channel 14 which are connected in sequence; the first channel 11 and the third channel 13 are both conical structures, and the small ends of the first channel 11 and the third channel 13 are both set toward the negative direction of the Y axis.

[0022] After the needle 22 is inserted into the sealing gasket 15, the operator feels resistance, and a seal is first formed at the connection position of the first channel 11 and the second channel 12. When the first seal fails, the needle is pressed down each time a sample is injected to form a seal at the connection position of the third channel 13 and the fourth channel 14. The sealing gasket 15 can continue to work, extend its service life and reduce the replacement frequency.

[0023] In more detail, when the sealing gasket 15 located at the wall portion of the first channel 11 and the second channel 12 is deformed due to long-term use, the operator can continue to deepen the insertion depth of the needle 22 when he can feel the resistance is reduced or the seal is not tight after inserting the needle 22 into the sealing gasket 15.

[0024] Since the needle 22 is also tapered, its diameter increases from bottom to top. Therefore, when the sealing gasket 15 is slightly deformed and loosened, the needle 22 is allowed to continue to extend downward, so that the contour of the needle 22 with a larger diameter than the original diameter can be closely matched with the sealing channel again. When it feels loose again, it continues to extend downward until the sealing gasket 15 on the wall of the first channel 11 and the second channel 12 is fatigued, aged, and fails. Then it enters the third channel 13 and the fourth channel 14 to re-form the sealing point. Therefore, this solution has the function of multiple sealing.

[0025] In addition, the sealing effect formed by the needle 22 at the connection position between the first channel 11 and the second channel 12 is closer to a line seal rather than a surface seal, because the injection needle 2 needs to frequently pierce the needle seal, which is a dynamic seal, and the needle 22 is also conical, and the line seal can be sealed along the contour of the injection needle 2, which can better fill the gap between the needle 22 and the sealing pad 15. Therefore, the line seal can usually withstand higher pressure, so for the injection needle 2, the line seal is better than the surface seal.

[0026] Specifically, the sealing gasket 15 includes a first cylinder and a second cylinder that are integrally formed, and the diameter of the first cylinder is larger than the diameter of the second cylinder; the sealing hoop 16 is in the shape of a shell, which is tightly connected to the second cylinder, and the lower end surface of the first cylinder is supported on the upper plane of the sealing hoop 16; the strength of the sealing hoop 16 is greater than the strength of the sealing gasket 15.

[0027] When the gasket 15 expands under stress, the sealing hoop 16 will protect the gasket 15, reduce its deformation, and extend the service life of the gasket 15. The sealing hoop 16 can provide additional support and rigidity, so that the gasket 15 is not easily deformed or deforms less when under pressure. When the gasket 15 is under pressure, the sealing hoop 16 can share part of the load and reduce the degree of deformation of the gasket 15. And the sealing hoop 16, as an external protective layer, can reduce the external wear of the gasket 15 during use.

[0028] The sealing support 3 has a through hole extending axially therethrough, and a steel tube 5 is fixedly connected to the through hole, and both ends of the steel tube 5 extend out of the sealing support 3; the internal cavity 51 of the steel tube 5 is connected to the fourth channel 14. One end of the steel tube 5 extending out of the sealing support 3 contacts the sealing gasket 15 to form a seal, and the other end is connected to the six-way valve on the chromatograph, so that the sample in the injection needle 2 flows through the internal channel of the sealing gasket 15, the internal cavity 51 of the steel tube 5, and the six-way valve into the chromatographic column or mass spectrometer.

[0029] Preferably, the fourth channel 14 is cylindrical, and its diameter is equal to the diameter of the small end of the third channel 13; the diameter of the small end of the third channel 13 is smaller than the diameter of the small end of the first channel 11. By setting the first channel 11 with a large tapered hole and the third channel 13 with a small tapered hole, the aperture can be gradually reduced to match the cavity 51 in the steel pipe 5 below. The aperture of the cavity 51 and the aperture of the fourth channel 14 should be kept as close as possible to achieve the purpose of reducing the dead volume. (Note: The dead volume refers to the space from the sampler inlet to the detector flow cell that is not occupied by the stationary phase. The method of reducing the dead volume can include reducing the length of the connecting pipeline or reducing the diameter of the connecting pipeline.) Among them, the aperture of the large end of the large tapered hole is larger than the actual diameter of the injection needle 2, which plays a guiding role for the injection needle 2 to penetrate into the channel of the sealing gasket 15, making it easier for the injection needle 2 to penetrate smoothly and form a seal.

[0030] When this solution is implemented, the longitudinal section of the first channel 11 passing through the axis is an isosceles trapezoid, and the angle between the intersection of the extension lines of its two hypotenuses is 20 to 30 degrees, preferably 25 degrees. The diameter of the large end of the first channel 11 is 1 mm to 1.2 mm, preferably 1.1 mm. The diameter of the small end of the first channel 11 is preferably 0.3 mm, the diameter of the fourth channel 14 is preferably 0.2 mm, and the height of the sealing gasket 15 is preferably 4.5 mm. The market mostly uses two types of steel pipes 5 with a cavity 51 aperture of 0.005 inches (0.127 mm) and an aperture of 0.01 inches (0.254 mm). The aperture of the channel in the sealing gasket 15 is reduced from Φ0.3 mm to Φ0.2 mm, which can better match the specifications of the two steel pipes 5.

[0031] As an embodiment of the present invention, refer to Figure 2 , the second channel 12 can be a conical structure, with its small end facing the positive direction of the Y-axis; the diameter of the small end of the second channel 12 is equal to the diameter of the small end of the first channel 11, and the diameter of the large end is equal to the diameter of the large end of the third channel 13. This design is more conducive to the needle 22 to form a line seal. The diameters between the first channel 11 and the second channel 12 are both variable diameters, and the directions of the connection between the two channels are opposite. The diameter of the connection is exactly the minimum diameter of the two channels. The end of the needle 22 can just be stuck at the minimum diameter of the first channel 11 and the second channel 12 to form a line seal. Since the diameter of the second channel 12 gradually increases, the needle 22 located in the second channel 12 does not contact the wall of the second channel 12, so the seal at this time is closer to a line seal.

[0032] As another embodiment of the present invention, refer to Figure 1 The second channel 12 may be a cylindrical structure, and the diameter of the second channel 12 is equal to the diameter of the small end of the first channel 11, and equal to the diameter of the large end of the third channel 13. The second channel 12 of the cylindrical structure can appropriately reduce its channel volume relative to the conical structure, which is conducive to reducing dead volume.

[0033] In summary, the present solution improves the channel shape so that the sealing gasket 15 has multiple sealing functions, thereby extending its working time, extending its service life and reducing the replacement frequency.

Claims

1. A leak-proof needle seal, characterized in that: The invention comprises a sealing assembly (1) into which a needle head (22) of an injection needle (2) extends, and a sealing support (3) is fixedly connected to the lower end of the sealing assembly (1); the sealing assembly (1) comprises a sealing gasket (15) and a sealing hoop (16) sleeved on the outside of the sealing gasket (15); The sealing gasket (15) is provided with a channel extending axially therethrough, the channel comprising a first channel (11), a second channel (12), a third channel (13) and a fourth channel (14) which are connected in sequence; the first channel (11) and the third channel (13) are both conical in structure, and the small ends of the first channel (11) and the third channel (13) are both arranged toward the negative direction of the Y axis.

2. The anti-leakage needle seal according to claim 1, characterized in that: The second channel (12) is a conical structure, with its small end facing the positive direction of the Y axis.

3. The anti-leakage needle seal according to claim 1, characterized in that: The second channel (12) is a cylindrical structure, and the diameter of the second channel (12) is equal to the diameter of the small end of the first channel (11), and is equal to the diameter of the large end of the third channel (13).

4. The anti-leakage needle seal according to claim 1, characterized in that: The sealing gasket (15) comprises a first cylinder and a second cylinder formed in one piece, the diameter of the first cylinder being greater than the diameter of the second cylinder; the sealing hoop (16) is in the shape of a sleeve shell and is tightly connected to the second cylinder, the lower end surface of the first cylinder is supported on the upper plane of the sealing hoop (16); the strength of the sealing hoop (16) is greater than the strength of the sealing gasket (15).

5. The anti-leakage needle seal according to claim 1, characterized in that: The sealing support (3) is provided with a through hole axially penetrating therein, a steel pipe (5) is fixedly connected to the through hole, and both ends of the steel pipe (5) extend out of the sealing support (3); the internal cavity (51) of the steel pipe (5) is in communication with the fourth channel (14).

6. The leak-proof needle seal according to claim 1, characterized in that: The longitudinal section of the first channel (11) passing through the axis is an isosceles trapezoid, the angle between the intersection of the extension lines of the two hypotenuses is 20-30°, and the diameter of the large end of the first channel (11) is 1 mm-1.2 mm.

7. The anti-leakage needle seal according to claim 5, characterized in that: The fourth channel (14) is a cylinder, and its diameter is equal to the diameter of the small end of the third channel (13); the diameter of the small end of the third channel (13) is smaller than the diameter of the small end of the first channel (11).

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